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Date: Thu, 21 Jan 2010 11:48:19 +0100
From: Olivier Houchard <mlfbsd@kanar.ci0.org>
To: Sebastian Huber <sebastian.huber@embedded-brains.de>
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Cc: FreeBSD-Hackers <hackers@freebsd.org>
Subject: Re: ARM and structure size boundary
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On Thu, Jan 21, 2010 at 11:21:56AM +0100, Sebastian Huber wrote:
> Hi,
> 

Hi Sebastian,

> on ARM the GCC has an option for the structure size boundary:
> 
> http://gcc.gnu.org/onlinedocs/gcc/ARM-Options.html#ARM-Options
> 
> In the GCC sources (gcc/config/arm) you see that NetBSD changes the default
> value to 8 from 32.
> 
> For FreeBSD I did not found something similar.  What value is used on FreeBSD
> by default?
> 
> This value is (or was) important for the network stack.  Do you know if the
> current FreeBSD network stack is dependent on this value?  In the file
> gcc/config/arm/netbsd.h (GCC sources) is a comment about this topic.
> 
> Have a nice day!
> 

FreeBSD uses the default value of 32. The NetBSD comment states NetBSD has
to use 8, because this is what some buggy code expects in their kernel (or
expected at some point, no clue if it's still there). Nothing in the network
stack, or anywhere in the kernel, should depend on it.

Regards,


Olivier